In a mobile communications system, a receive end generally needs to perform channel estimation on a current transport channel after receiving data, so as to perform balance processing on the received data, and further eliminate impact of the transport channel on a signal. Specifically, a transmit end transmits, on some REs (resource element) of each PRB (physical resource block) pair, pilot signals known by the transmit end and the receive end, so as to implement that the receive end performs channel estimation by using the pilot signals.
Currently, pilot signals are transmitted in a PRB pair that occupies 12 subcarriers in a frequency domain, so as to perform channel estimation by using the pilot signals. Specifically, a pilot signal is transmitted on an intermediate SC-FDMA (single carrier frequency division multiple access) symbol in each slot of the PRB pair. The PRB pair is an uplink subframe of an FDD (Frequency Division Duplexing) radio frame or an uplink subframe of a TDD (Time Division Duplexing) radio frame. Each PRB pair includes two slots. Each PRB pair occupies 12 subcarriers in the frequency domain. In a common CP structure, each PRB pair occupies 14 SC-FDMA symbols in a time domain, and in an extended CP structure, each PRB pair occupies 12 SC-FDMA symbols in the time domain.
However, when a pilot signal is transmitted in a common subframe that occupies 12 subcarriers in the frequency domain, a transmission distance of a PRB pair cannot be increased for a system with a limited power, which causes a relatively small uplink coverage range.